简介：在这份报纸，在椰子(Cocusnucifera)的一个agroforestry系统骑车的生物资源生产率和营养素与菠萝(波罗comosus)在实行套种被学习了。结果证明这个生态系统的生物资源生产率是47460kg...hm2...一?1，它4.3倍于纯椰子种植园的。在N的生物骑车，P。K元素，全部的年度保留是559.470kg...hm?2，年度回来是410.745kg...hm?2，年度举起是970.475kg...hm?2分别地。在三个滋养的元素的平均发行量率(N，P，K)是42.32%，它在纯椰子看台多于那是27.53%。椰子与菠萝在实行套种被证明是最佳之一文化模式，它有更高的生物资源生产率，和在热带区域的环境资源的更好的用法效率。

简介：为了确定黄土高原地区现有刺槐林改造的最佳间伐强度，１９９５年秋季对密度为２２２０株／公顷的９年生刺槐林进行了三种不同强度的间伐．通过间伐，降低了群落密度，减少了林冠截留率，增加了植树带内的汇流量，根系层内的土壤水分条件得到明显的改善．当间伐后的林分密度为１１１０株／公顷时，生长季内植树带土壤水分提高约４０％．随着间伐强度的增大，林木的水分生产函数曲线由直线上升变为以对数曲线上升；当间伐强度达到某一值时（保留密度为１１１０株／公顷），林木水分生产力随蒸腾量的变化曲线为抛物线．这表明此时水分已不再是林木生产的限制因子，在这种间伐强度条件下，单株林木和整个林分的水分生产力分别达到６０１７１ｇ·ｋｇ－１·ｍｍ－１和１４９７７７ｋｇ·ｈｍ－２·ｍｍ－１，因此将这一强度定为黄土高原地区刺槐林间伐的最佳强度．

简介：Plantationresourceisanimportantcomponentofforestresources.OverallplantationqualityisnothighinChina,andtheproblemslikelowgrowth,lowpreservingrateandlowproductivityarecommonlyobserved.Thispaperreviewedthehistoricalbackgroundoftheresearchonplantationproductivity,describedfactorsaffectingplantationproductivityincludingsiteconditions,initialplantingdensity,thinningmeasures,groundclearance,andcontinuousplantedalgebraandfertilization.Finally,itwasproposedtocarryoutkeytechnologysystemresearchonplantationproductivitymaintenanceandstrengthentheresearchonthelong-termness,systematicdevelopmentandmulti-purposeofplantationproductivity.

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简介：Directseededriceispromisingalternativetotraditionaltransplanting,butrequiresappropriatecropandwatermanagementtomaintainyieldperformanceandachievehighwaterproductivity.Presentstudyevaluatedtheeffectofseedprimingandirrigationoncropestablishment,tillering,agronomictraits,paddyyield,grainqualityandwaterproductivityofdirectseededriceinalternatewettinganddrying(DSR-AWD)incomparisonwithdirectseededriceatfieldcapacity(DSRFC).Seedprimingtreatmentswereosmo-primingwithKCl(2.2%),CaCl2(2.2%)andmoringaleafextracts(MLE,3.3%)includinghydro-primingascontrol.Amongthetreatments,seedosmo-primedwithMLEemergedearlierandhadhigherfinalemergence,followedbyosmo-primingwithCaCl2.TilleringemergencerateandnumberoftillersperplantwerethehighestforseedprimingwithCaCl2inDSRAWD.Totalproductiveandnon-productivetillers,paniclelength,biologicalandgrainyields,harvestindexwerehighestforseedprimingwithMLEorCaCl2inDSR-AWD.Similarly,grainquality,estimatedintermsofnormalgrains,abortiveandchalkygrains,wasalsothehighestinDSR-AWDwithMLEosmo-priming.BenefitcostratioandwaterproductivitywasalsothehighestinDSR-AWDforseedprimingwithMLE.Inconclusion,seedprimingwithMLEorCaCl2canbesuccessfullyemployedtoimprovethedirectseededriceperformancewhenpracticedwithalternatewettinganddryingirrigation.

简介：Background:Withthelossofspeciesworldwideduetoanthropogenicfactors,especiallyinforestedecosystems,ithasbecomemoreurgentthanevertounderstandthebiodiversity-ecosystemfunctioningrelationship(BEFR).BEFRresearchinforestedecosystemsisverylimitedandthusstudiesthatincorporategreatergeographiccoverageandstructuralcomplexityareneeded.Methods:Wecompiledground-measureddatafromapprox.onehalfmilionforestinventorysampleplotsacrossthecontiguousUnitedStates,Alaska,andnortheasternChinatomaptreespeciesrichness,foreststocking,andproductivityatacontinentalscale.Basedonthesedata,weinvestigatedtherelationshipbetweenforestproductivityandtreespeciesdiversity,usingamultipleregressionanalysisandanon-parametricapproachtoaccountforspatialautocorrelation.Results:Ingeneral,forestsintheeasternUnitedStatesconsistedofmoretreespeciesthananyotherregionsinthecountry.ThehighestforeststockingvaluesovertheentirestudyareawereconcentratedinthewesternUnitedStatesandCentralAppalachia.Overall,96.4%ofsampleplots(477,281)showedasignificantpositiveeffectofspeciesrichnessonsiteproductivity,andonly3.6%(17,349)hadaninsignificantornegativeeffect.Conclusions:Thelargenumberofground-measuredplots,aswellasthemagnitudeofgeographicscale,renderedoverwhelmingevidenceinsupportofapositiveBEFR.Thisempiricalevidenceprovidesinsightstoforestmanagementandbiologicalconservationacrossdifferenttypesofforestedecosystems.Foresttimberproductivitymaybeimpairedbythelossofspeciesinforests,andbiologicalconservation,duetoitspotentialbenefitsonmaintainingspeciesrichnessandproductivity,canhaveprofoundimpactsonthefunctioningandservicesofforestedecosystems.

简介：在巴基斯坦的瑞斯生产是由与流行种的技术相关的许多因素的限制。关于新种的技术的可行性的研究(在公寓上的直接播种，在公寓上移植，在山脉上的直接播种，在山脉并且降落伞种上移植)在里面移植，直接湿种子的米饭在DeraIsmail被承担巴基斯坦的北方的Khanregion韦斯特边疆省在2002和2003期间。在种的技术之中，为收益形成和经济评估的最好的表演以在两年期间在公寓上移植闻名。中国降落伞种技术也在大多数参数显示出很有希望的结果。在山脉上的直接播种不能为佼佼者在在两个都收割季节期间种的公寓和降落伞上移植。调查结果结束了与在在区域被练习的所有另外的种的技术上在公寓上移植的传统的米饭一起种技术的降落伞的可行性。

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简介：Background:Forestmanagementdecisionsarebasedonexpectationsoffuturedevelopments.Forsounddecisionsitisessentialtoaccuratelypredicttheexpectedvaluesinfuturedevelopmentsandtoaccountfortheirinherentuncertainty,forexampletheimpactofclimatechangeonforests.Changingclimaticconditionsaffectforestproduaivityandaltertheriskprofileofforestsandforestenterprises.IntensifyingdroughtstressisseenasonemajorriskfactorthreateningforestmanagementinthenorthGermanlowlands.Droughtstressreducestreegrowthandvitalityandmighteventriggermortality.Butsofar,itisnotpossibletoquantifyeffectsofapersistentdryerclimateonforestproductivityatalevelsuitableforforestmanagement.Methods:Weapplyawell-establishedsingle-treeforestgrowthsimulatortoquantifytheeffectofpersistentdryerclimatesonfutureforestproductivity.WeanalysethegrowthofScotspine(PinussylvestrisL.);Europeanbeech{FagussylvoticoL.)andoak{QuercusroburL.andQuercuspetraeo(Matt.)Liebl.)intwoforestregionsinthenorthGermanlowlandsforatimeintervalof60yearsuntil2070.Thegrowthresponseunderthreedifferentclimateprojectionsiscomparedtoabaselinescenario.Results:Theresultsshowcleardifferencesinvolumeincrementtopersistentdryerclimatesbetweentreespecies.Thefindingsexhibitregionaldifferencesandtemporaltrends.WhilemeanannualincrementatbiologicalrotationageofScotspineandoakpredominantlybenefitsfromtheprojectedclimateconditionsuntil2070,beechmightsufferlossesofupto3m3-ha’-yr1dependingonclimatescenarioandregion.However,intheprojectionperiod2051to2070theuncertaintyrangescomprisepositiveaswellasnegativeclimaticeffectsforallspecies.Conclusions:Theprojectedchangesinforestgrowthserveasquantitativecontributionstoprovidedecisionsupportintheevaluationof,forexample,speciesfuturesitesuitabilityandtimbersupplyassessments.Theanalysiso

简介：在modulating植物生产率的土壤pH的潜在的角色根据干燥质量被估计，在0.25m2空铅形式收获了，在北希腊的二块低生产率的高地草地使遭到了到年度因素的氮(N)和磷(P)授精(15gNm−2year−1和10gPm−2year−1)在最小上3年的时期。在这些特别条件下面，一种积极关系将在土壤pH和植物生产率之间存在，进一步，营养素的那N或P化肥应用限制系统，这被假设，将导致一变弱这种积极关系。一种重要积极关系在其它在二个学习区域和一个积极趋势之一在土壤pH和植物生产率之间被证实。而且，植物生产率增加，后面的授精，看起来在土壤pH植物生产率关系上有有害效果。调查结果支持原来的假设并且加强想法种调停差异的土壤pH植物生产率关系是发生在更多的“typical”下面的更强烈的植物种形成的结果更高的pH在的土壤条件与热带区域对比适度。

简介：Withdecreasingavailabilityofwaterforagricultureandincreasingdemandforriceproduction,anoptimumuseofirrigationwaterandphosphorusmayguaranteesustainablericeproduction.Fieldexperimentswereconductedin2003and2004toinvestigatetheeffectofphosphorusandirrigationlevelsonyield,waterproductivity(WP),phosphorususeefficiency(PUE)andincomeoflowlandrice.Theexperimentwaslaidoutinrandomizedcompleteblockdesignwithsplitplotarrangementsreplicatedfourtimes.Mainplotconsistedoffivephosphoruslevels,viz.0(P0),50(P50),100(P100),150(P150),and200(P200)kg/hm2,whilesubplotscontainedofirrigationtimes,i.e.8(I8),10(I10),12(I12),and14(I14)irrigationlevels,eachwithawaterdepthof7.5cm.MeanvaluesrevealedthatP150incombinationwithI10producedthehighestpaddyyield(9.8t/hm2)andnetbenefit(1231.8US$/hm2)amongallthetreatments.PhosphorusenhancedWPwhenappliedinappropriatecombinationwithirrigationlevel.ThehighestmeanWP[13.3kg/(hm2?mm)]couldbeachievedatP150withI8anddecreasedwithincreaseinirrigationlevel,whilethehighestmeanPUE(20.1kg/kg)couldbeachievedatP100withI10anddiminishedwithhigherPlevels.TheoverallresultsindicatethatP150alongwithI10wasthebestcombinationforsustainablericecultivationinsiltyclaysoil.

简介：陆上的碳周期和全球大气的CO2预算是在全球气候变化研究的重要foci。模仿的网陆上的生态系统的主要生产率(NPP)为碳周期研究是重要的。在这研究，plant-atmosphere-soil连续统氮(N)骑车的模型被开发并且合并了到北方的生态系统生产率模拟器(BEPS)模型。与在1km分辨率的确定的数据库(叶区域索引，陆地盖子，每日的气象学数据，植被和土壤)，每天NPP印射因为在2007的澜沧江山谷被生产，并且NPP的空间时间的模式和它对土壤N水平的回答的机制进一步被探索。全部的NPP和在2007的澜沧江山谷的吝啬的NPP是66.5TgC和416g

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